#2451 has_many :through associations give different results depending on eager-loading via :include - Ruby on Rails

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#2451 ✓stale

has_many :through associations give different results depending on eager-loading via :include

Reported by David Lee | April 7th, 2009 @ 11:40 PM | in 3.x


class User
  has_many :comments
  has_many :posts, :through => :comments
end

class Comment
  belongs_to :user
  belongs_to :post
end

x = User.create
x.comments.create :post_id => nil

x.posts #=> []

x = User.find :first

x.posts #=> []

x = User.find :first, :include => [:posts]
x.posts #=> [nil] !!!

I'm not sure if posts should return [] or [nil], but the result should be consistent regardless of whether the association was eager-loaded or not.

Comments and changes to this ticket

Tatsuya Ono June 16th, 2009 @ 01:40 AM
- no changes were found...
- ticket-2451-patch.diff 1.3 KB
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Tatsuya Ono June 16th, 2009 @ 01:40 AM
I wrote a patch for this issue against 2-3-stable.

I also put a simple project on github which allows you to reproduce this issue easily.
http://github.com/ono/eager_load_issue/tree/master

Clone it then run rake test. It will be failed despite for it should be passed.
```
    # sets up data
    
    u1 = User.find :all
    u2 = User.find :all, :include=>['posts_commented']
    assert_equal u1[0].posts_commented.size, u2[0].posts_commented.size
```
You will succeed to pass the test if you apply the patch attached.
Jeremy Kemper May 4th, 2010 @ 06:48 PM
- Milestone changed from “2.x” to “3.x”
[bulk edit]
Jon Leighton December 16th, 2010 @ 12:35 AM
- Assigned user set to “Aaron Patterson”
- Importance changed from “” to “”
Can this ticket be closed or at least marked as stale please? If you look at association_preload.rb in current master, you will see that it does Array.wrap(associated_record), which deals with the case of associated_record being nil, which is the source of the problem reported.
Aaron Patterson December 16th, 2010 @ 01:46 AM
- State changed from “new” to “stale”
@Jon yes. Marking as stale. :-)